1. Field of the Invention
The present invention relates to material-handling systems, and more particularly to computerized systems for tracking the real-time locations of shipping containers.
2. Description of Related Art
On the West Coast of the United States, shipping container handling volumes have been increasing dramatically. In 1999, container twenty-foot equivalent units (TEU's) increased almost 10% to 8 M TEU's. This was half of the total TEU's for the entire country. Ten years ago, the West Coast was handling less than 4 M TEU's.
Such increases in handling volume are adversely affecting real-time order visibility. But every partner to the transactions needs to have access to location information throughout a container's journey. In port, containers are routinely not visible to the consignees, and this produces some consternation.
Yard operations are the most time consuming in overall average transactions. Out-gate operations take less time, guard operations require less than that, and in-gate operations are the least time consuming. During yard operations, a yard clerk must accompany the truck driver to validate the correct container for pick-up. But if the container is not where it is supposed to be, the typical yard clerk wanders around the yard looking for it. Then the equipment operator and truck driver have to be radioed to come to the new location. Even so, the right container might be buried by others that need to be moved out of the way, all while the yard clerk and truck driver are waiting. It would be better if the equipment operator could have the container free to load and in a verified location by the time the truck arrives.
Prior art systems and methods have experimented with attaching marks, markers, bugs, radios, GPS equipment, and other devices to the shipping containers. These devices then ride along through the entire trip. But putting such things on each container is expensive, and the devices are often blocked for some reason and not accessible. Device incompatibilities also are common because no world standard exists. It's hard enough to stick with a single standard within one storage and transfer yard.
The use of simple identification labels on material and the tracking of them is described by Harold Terrence Salive, et al., in U.S. Pat. No. 5,725,253, issued Mar. 10, 1998. The labels are visual graphics that are captured by a digital imaging camera.
Joseph Radican describes a container monitoring system and method in U.S. Pat. No. 5,712,789, issued Jan. 27, 1998. The system can generate status reports for customers, suppliers, and shippers about their respective containers. A container management information system is updated with container identification and location data.
A GPS navigation receiver is coupled with a cellphone, and both are attached to a shipping container in U.S. Pat. No. 5,835,377, issued Nov. 10, 1998, to Ronald Bush. Such tracking module is described as being built into each shipping container.
Each such patent mentioned herein is incorporated by reference.